1. Field of the Invention
The present invention belongs to a technical field of electric connectors for cards, which receive cards such as IC cards, and particularly relates to an electric connector for cards, which is provided with an ejection mechanism for ejecting an inserted card.
2. Related Art
As electric connectors for cards of this kind, connectors are known, which are provided with an ejection mechanism using a heart-shaped cam groove. For example, Japanese Patent unexamined publication gazette Heisei 11-224726 discloses an electric connector for cards, which comprises a housing having contacts for connecting a card, a frame that supports a card in a disconnectable manner, and a flexible pushrod that can be reciprocated between a pushed-in position and a protruding position, wherein when a card is inserted, the pushrod is set in the pushed-in position by a locking mechanism having a heart-shaped cam groove, and under this condition, if the pushrod is pushed, locking of the pushrod will be undone and the pushrod will shift to the protruding position, and under this condition, if the pushrod is pushed, the card will be ejected by means of the pushrod. In this connector, a part of the pushrod is made to trace the heart-shaped cam groove, and the connector is provided with an ejection arm that can be engaged with and disengaged from the pushrod, and if the pushrod is pushed when it is in the protruding position, the pushrod will trace the heart-shaped cam groove and the pushrod will drive the ejection arm to discharge the card by means of the ejection arm, and the pushrod is made to be locked in the pushed-in position by the heart-shaped cam groove. Moreover, when the pushrod is in the pushed-in position, the pushrod is locked by means of the heart-shaped cam groove and the pushrod and the ejection arm are not engaged with each other, and under this pushed-in condition if the pushrod is pushed, the pushrod being free from the ejection arm will trace the heart-shaped cam groove to come to the protruding position.
In this connector, a part of the pushrod is made to trace the heart-shaped cam groove, and as the pushrod is made of a metal and the heart-shaped cam groove is made of a resin, the wear is excessive. To reduce this wear and achieve smooth tracing, grease is applied to the contacting parts and the contacting part of the metallic side is smoothed. Such measures, however, increase the cost. Furthermore, as tracing of a part of the pushrod in the heart-shaped cam groove is effected by movement in a plane, the ejection mechanism tends to be bulky. Moreover, to ensure smooth tracing, it is necessary to carefully assemble the pushrod, heart-shaped cam groove, etc. This difficulty of assembly results in higher cost.
The present invention was made in view of the above-mentioned points, and one object of the invention is to provide a member, which engages with or disengages from an ejection mechanism for loading and unloading a card and gives an ejecting force to the ejection mechanism when the member engages with the ejection mechanism, and switching between engagement and disengagement is effected by rotation of the member, and this rotation is effected by use of wave-shaped cams to eliminate needs of countermeasures against friction of the member to reduce costs, and to improve space-saving and ease in assembly to further cost reduction.
To accomplish the above-mentioned object, the electric connector for cards of the present invention comprises: a body into which a card is to be inserted; an ejection mechanism, which has a slider that linearly reciprocates between a first position and a second position, said ejection mechanism being provided on said body, in said ejection mechanism when a card is inserted into a connection position, the slider will be pushed by the card to move from the second position to the first position, and when the slider is pushed back from the first position to the second position, said ejection mechanism will push out the card from the connection position in a discharge direction; a rotary shaft, of which center of rotation is parallel to the direction of shift of the slider and is kept away by an offset from a passage space of the slider, said rotary shaft being provided, on its external circumferential face near its top end, with an engagement part and an escapement part being formed in the circumferential direction, the engagement part extending in the radial direction by more than the offset from the center of rotation of said shaft, the escapement part extending in the radial direction by less than the offset from the center of rotation of said shaft, said shaft being provided with a guide protrusion formed closer to the root end of said shaft than the engagement part and the escapement part, and said shaft being provided, on its end face of the root end, with a wave-shaped cam of a shifting side, the cam being continuous in the circumferential direction; a holder cylinder, which is provided on the body, into which, on its top end side, said rotary shaft, at least its part from the guide protrusion down to the root end is fitted shiftably in the axial direction and rotatably, said holder cylinder being provided, on its inner circumferential face, with two kinds of guide grooves, one kind being short and the other being long, the guide grooves extending from the top end in the axial direction to receive the guide protrusion of said rotary shaft, the longer guide groove or first guide groove being formed in such a position on the circumference that when the guide protrusion enters into the first guide groove, the engagement part will get into the passage space of the slider and engage with the slider on a side to prevent its advancement, and the shorter guide groove or second guide groove being formed in such a position on the circumference that when the guide protrusion enters into the second guide groove, the engagement part will move away from the passage space of the slider and the escapement part will be kept away from the passage space of the slider; an energizing member for energizing said rotary shaft towards said holder cylinder; and a pushrod, which is fitted into said holder cylinder on its root end side in such a way that said pushrod does not come off said holder cylinder and said pushrod can be shifted in the axial direction and is prevented from rotation, said pushrod having, on the end face of the top end, a fixed-side wave-shaped cam that contacts the shifting-side wave-shaped cam of the rotary shaft and is formed continuously in the circumferential direction, the root end of said pushrod being formed into a button, and when the button is pushed and released, said pushrod will reciprocate in the axial direction, and in the outward movement said pushrod will push said rotary shaft and make the guide protrusion come out of said holder cylinder, and said pushrod will make the shifting-side wave-shaped cam slide along the fixed-side wave-shaped cam to rotate said rotary shaft in one direction, and in the homeward movement said pushrod will put the guide protrusion into an adjoining guide groove.
Actions of this electric connector for cards are as follows. In the initial position, the guide protrusion of the rotary shaft is in the shorter groove or second guide groove of the holder cylinder. As the second guide groove is shorter, the length of insertion of the rotary shaft into the holder cylinder gets shorter, and accordingly, the pushrod gets into the holder cylinder deeper, and the protrusion of the pushrod from the holder cylinder is shorter. Under this condition, the engagement part of the rotary shaft moved away from the passage space of the slider, and the escapement part is kept away from the passage space of the slider. Accordingly, the slider of the ejection mechanism has been advanced, by the card that is inserted into the connection position, from the second position to the first position. This advancement, however, does not bring about contact between the slider and the rotary shaft nor any movement of the rotary shaft and the pushrod.
When the card is to be discharged, first the button is depressed once by working against the energizing force of the energizing member. The pushrod will reciprocate one cycle in the axial direction. In the outward movement, the pushrod will push said rotary shaft to make the guide protrusion come out of the holder cylinder and have the shifting-side wave-shaped cam slide along the fixed-side wave-shaped cam to rotate the rotary shaft in one direction. In the homeward movement, the guide protrusion will get into the adjoining first guide groove. As the first guide groove is longer, the length of insertion of the rotary shaft into the holder cylinder gets longer, and the pushrod will be pushed out from the holder cylinder by the difference between the lengths of both the guide grooves, and the length of protrusion of the pushrod from the holder cylinder will get longer in comparison with that in the initial position. In this case, the engagement part of the rotary shaft will come into the passage space of the slider and will engage with the slider on the side of preventing its advancement. Accordingly, when the button is pressed once more against the energizing force of the energizing member, the pushrod will reciprocate one cycle in the axial direction, and in the outward movement, the pushrod will push the rotary shaft to make the guide protrusion come out of the holder cylinder and have the shifting-side wave-shaped cam slide over the fixed-side wave-shaped cam to rotate the rotary shaft in one direction. In the homeward movement, the guide protrusion will get into the adjoining second guide groove and return to the initial position. During this course, in the outward movement, the engagement part engages with the slider and pushes back the slider from the first position to the second position, and the card will be pushed out from the connection position in the discharge direction.
As described above, this electric connector for cards is provided with a rotary shaft, which engages with or disengages from the slider and gives an ejecting force to the slider when the rotary shaft engages with the slider, and switching between the engagement with and disengagement from the slider is effected by rotation of the rotary shaft, and this rotation is effected by use of wave-shaped cams. As a result, the rotary shaft, holder cylinder, pushrod, etc. can be formed of the same material, and countermeasures against friction between members are not required in comparison with the connector with an ejection mechanism using a heart-shaped cam groove. Moreover, as members make rotary shifts rather than shifts in a plane, ease of assembly is improved.
This electric connector for cards is provided with a rotary shaft, which engages with or disengages from the slider and gives an ejecting force to the slider when the rotary shaft engages with the slider, and switching between the engagement with and disengagement from the slider is effected by rotation of the rotary shaft, and this rotation is effected by use of wave-shaped cams. As a result, the rotary shaft, holder cylinder, pushrod, etc. can be formed of the same material. Hence in comparison with a connector with an ejection mechanism using a heart-shaped cam groove, countermeasures against friction of members are not needed, and this contributes to reduction in cost. Moreover, as the members do not shift in a plane and the members make rotary shifts, space-saving is improved. Furthermore, cost can be reduced further through improvement in ease of assembly.